Bromides preparation

To a solution of propargylmagnesium bromide, prepared according to Chapter II,... 

To a mixture of 100 ml of THF and 0.10 mol of the epoxide (note 1) was added 0.5 g Of copper(I) bromide. A solution of phenylmagnesium bromide (prepared from 0.18 mol of bromobenzene, see Chapter II, Exp. 5) in 130 ml of THF was added drop-wise in 20 min at 20-30°C. After an additional 30 min the black reaction mixture was hydrolysed with a solution of 2 g of NaCN or KCN and 20 g of ammonium chloride in 150 ml of water. The aqueous layer was extracted three times with diethyl ether. The combined organic solutions were washed with water and dried over magnesium sulfate. The residue obtained after concentration of the solution in a water-pump vacuum was distilled through a short column, giving the allenic alcohol, b.p. 100°C/0.2 mmHg, n. 1.5705, in 75% yield. 

Bromination of methane is exothermic but less exothermic than chlorination The value calculated from bond dissociation energies is AH° = -30 kJ Al though bromination of methane is energetically fa vorable economic considerations cause most of the methyl bromide prepared commercially to be made from methanol by reaction with hydrogen bromide... 

A 3-I. three-necked, round-bottom flask is fitted with a mechanical stirrer through a mercury seal, a reflux condenser and a i-l. separatory funnel. A mixture of 200 g. (r mole) of 2,3-dibromopropene (Org. Syn. 5, 49) and 200 cc. of dry ether is added. The flask is now cooled in an ice bath, the stirrer is started, and one molecular equivalent of cyclohexylmagnesium bromide, prepared from 31 g. of magnesium, 204 g. of cyclohexyl bromide and 400 cc. of dry ether (Note i) is added at such a rate that the mixture refluxes gently (Note 2). The addition takes about one-half to three-quarters of an hour. Two layers are formed and magnesium bromide may or may not separate. 

The reaction of (54) and acetylenedimagnesium bromide, prepared from methylmagnesium bromide and acetylene, gave (55) in excellent yield instead of the expected bis-steroid (57). 

Aj Preparation of (2-Amino-5-ChlorophenyljPhenylmethaneimine (4356 CB) A solution of 228.7 g (1.5 mols) of 2-amino-5-chlorobenzonitrile in 1,800 ml of dry ether is added slowly in the course of about 3.5 hours to a solution of phenyl magnesium bromide prepared from 109 g (4.5 g-atoms) of magnesium turnings and 848 g (5.4 mols) of bromobenzene In 3,600 ml of anhydrous ether, and the mixture then heated under reflux for 15 hours. 

The residue was dissolved in 75 ml of tetrahydrofuran, treated with charcoal, and sodium sulfate and filtered. This solution was added to a solution in 250 ml of tetrahydrofuran of phenyl magnesium bromide prepared from 17.7 ml (0.17 mol) of bromobenzene. This mixture was stirred and heated under reflux for 1 hour. It was then cooled and diluted with 400 ml of ether and sufficient 3N hydrochloric acid to make it acidic. The aqueous phase was separated, adjusted to pH 8 with 3N sodium hydroxide and extracted 3 times with 200 ml of ether. The ether extracts were combined, washed with water and dried over sodium sulfate. The residue left on removal of the ether in vacuo was crystallized from petroleum ether to give 3.3 g of 7-chloro-2,3-dihvdro-1-methyl-5-phenvl-1 H-1,4-benzodiazepine, according to U.S. Patent 3,624,703. 

To a solution of thienyl magnesium bromide prepared from 21.4 g of magnesium and 144 g of 2-bromothiophene are added 39.B g of ethyl 4-dimethylaminocyclohexylcarboxylate. The mixture is ailowed to warm to room temperature and stirred for an additional six hours. The reaction mixture is then decomposed with dilute ammonium chloride solution and extracted with ether. The combined ether extracts are extracted thoroughiy with 10% hydrochloric acid and the acid solution made alkaline with ammonium hydroxide. The aqueous solution is extracted with chloroform which is then washed with water, dried and evaporated to a residue in vacuo. Recrystallization of the residue from hexane yields Oi.O -dithienyl-4-dimethyl-aminocyclohexyl carbinol, melting point 156°C to 157°C after recrystallization from benzene. 

Bromide. A 0.01 M solution of potassium bromide, prepared from the pure salt previously dried at 110°C, is suitable for practice in this determination. The experimental details are similar to those given above for chloride except that no methanol need be added. The titration cell may contain 10.00 mL of the... 

Farrow and Selwyn (479) found that the intramolecularly 5-coordinate, mixed triorganotin bromide, prepared by Noltes and his co-workers (63, 492), namely. 

A mixture of 1 g 2,4,6-trimethoxyben2yl trimethylsilyl ether 1578 and ethylmagne-sium bromide, prepared from 1 g ethyl bromide and 0.2 g Mg in 90 mb Et20, is heated under reflux for 30 min to give, on filtration through a layer of silica gel... 

Preparation of tetra(p-methoxymethyl) phenylphosphonium bromide — Preparation of a tetraarylphosphonium salt precursor to a pentaarylphosphorane... 

Dimethylprop-2-ynylsulfonium bromide, preparation, intermediate in furan synthesis, 53, 1... 

Alcohol. Along with several bromide preparations and paraldehyde, alcohol has often been used to relieve anxiety. Due to the marked untoward social and medical consequences of frequent use, alcohol has no place in the treatment of anxiety. Unfortunately, the inappropriate use of alcohol to self-medicate anxiety, depression, insomnia, or other symptoms often leads to alcoholism and therefore contributes to a signihcant public health problem. 

Bis(p-methoxyphenyl) ditelluride (typicalprocedure To a solution of p-methoxyphenyl-magnesium bromide (prepared from p-bromoanisole (5.82 g, 0.0311 mol) and Mg (1.0 g, 0.042 mol) in THF (20 mL)) is added Te shot (3.81 g, 0.0300 mol) at room temperature. The mixture is stirred under reflux for 3 h and then cooled to 0°C and treated with a sam-rated solution of NH Cl (20 mL vigorous evolution of gas). The mixture is filtered through Celite and the solids washed with saturated solution of NH Cl and ether. The organic phase is washed with brine and dried with Na2S04. Evaporation of the solvent and recrystaUiza-tion from CHClj/petroleum ether affords the pure product (5.16 g (75%) m.p. 57-59°C). 

Phenyl(p-methoxyphenyltelluro)acetylene (typical procedure To a solution of lithium phenylacetylide (20.0 mmol), prepared as described above, is added dropwise a solution of p-methoxyphenyltellurenyl bromide (prepared by adding bromine (1.60 g, 10.0 mmol)) in benzene (5 mL) to a solution of the corresponding ditelluride (4.69 g, 10 mmol) in THF (10 mL) at 0°C under Nj. The reaction mixture is stirred for 1 h at room temperature and then treated as described above to give the product (4.90 g (73%)), which is recrystallized from EtOH (m.p. 71-72°C). 

A solution of -1 mol of ethylmagnesium bromide (prepared from 1.10 mol of C2H5Br and Mg as described in ref. 4) in -1000 ml of THF (note 1) is heated to 50 C. Acetylene (note 2) is then introduced at a rate of 300-400 mVmin (flow meter) with vigorous stirring, while keeping the temperature between 50 and 55 C (note 3). The introduction of gas is stopped when the temperature has dropped to between 40 and 45 C (without external cooling). The jelly-like suspension is then heated for an additional 30 min at 50 C with introduction of N2 (300-500 m]/min, note 4)... 

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